The Great Stink of 1858: How London's Crisis Built the Modern Sewer System

Parliament Soaked Its Curtains in Lime Chloride and Still Couldn't Work: The Summer of 1858

In the summer of 1858, the smell rising from the River Thames in central London became so overpowering that Members of Parliament fled their riverside chambers and the House of Commons suspended sessions. Clerks soaked the curtains in chloride of lime — an early disinfectant — in an attempt to make the building usable. The Times called it "a stench so foul we may almost say we had smelt the atmosphere of Hades itself." Londoners had been living with a worsening Thames for decades, but the summer of 1858 was the point at which an institution powerful enough to commission a solution was itself made physically uncomfortable enough to act.

The Great Stink was the product of a specific technological catastrophe: the introduction of the water closet (flush toilet) to a city whose sewer system had been designed to handle rainwater, not human waste. The result was that hundreds of thousands of flush toilets were now emptying directly into the Thames, the same river from which much of London drew its drinking water. The city was, in the most literal sense, drinking its own sewage.

How London Got Into This Situation

Pre-industrial London managed human waste through a network of cesspools — underground brick chambers beneath houses that were periodically emptied by "nightsoil men" who carted the contents to market gardens outside the city as fertilizer. The system was unpleasant, inefficient, and occasionally catastrophic (cesspool collapses killed people), but it kept waste away from waterways and surface water sources.

The water closet changed everything. Patented in 1775 by Alexander Cumming and popularized through the 19th century, flush toilets used large quantities of water to transport waste and required connection to a drainage system. London's existing drains led to the Thames. Parliament, responding to public pressure to modernize sanitation, mandated in 1847 that all new buildings include water closets connected to the sewer network. The existing cesspools were ordered filled in. The cumulative effect was to redirect all of London's human waste — from roughly 2.5 million people by 1850 — directly into the Thames.

• By the early 1850s, an estimated 250 million gallons of sewage per day were entering the Thames
• The Thames's tidal flow prevented waste from washing out to sea; it simply oscillated back and forth through central London
• Drinking water suppliers extracted from the Thames upstream of their competitors' sewage outlets, but with no systematic treatment, the water remained contaminated

Cholera and the Miasma Theory Mistake

Three major cholera epidemics struck London in 1831–32, 1848–49, and 1853–54, killing roughly 50,000 Londoners combined. The dominant medical theory of the period held that cholera and other diseases spread through miasma — foul-smelling air arising from decomposing organic matter. This theory was wrong, but it had a paradoxically useful consequence: it meant that the Great Stink was perceived as a direct public health emergency, not merely a nuisance. The smell was itself understood as the mechanism of disease, making its elimination urgent.

Dr. John Snow's famous investigation of the 1854 Broad Street cholera outbreak — in which he traced the disease to a contaminated water pump by mapping cases, removed the pump handle, and demonstrated a waterborne rather than airborne transmission route — began to challenge the miasma theory. Snow's work was largely dismissed by the medical establishment at the time, but the engineer who designed London's solution arrived at the correct answer through the wrong reasoning: Joseph Bazalgette designed a system to remove sewage from the Thames (thus eliminating the smell and the miasma), which incidentally also removed the actual cause of cholera (fecal-oral contamination of drinking water).

Joseph Bazalgette and the Engineering Solution

Joseph William Bazalgette, chief engineer of the Metropolitan Board of Works, had been preparing plans for a comprehensive London sewer system since 1856. He had been blocked by bureaucratic indecision, cost disputes, and jurisdictional disagreements for two years. The Great Stink created a political emergency that dissolved every obstacle: Parliament passed the Metropolis Local Management Amendment Act in July 1858, giving the Metropolitan Board of Works emergency powers and £3 million in funding (approximately £350 million in 2023 terms). Work began that autumn.

Bazalgette's engineering genius was in future-proofing. When calculating pipe diameters, he was advised to use measurements based on current population projections. He doubled them, reasoning that London would continue to grow. His doubled pipes have handled the city's sewage for 160 years without requiring replacement of the main intercepting sewer structure. The only significant modification came in the 1990s when the Lee Tunnel and Tideway Tunnel (a £4.2 billion project completed in 2025) were added to handle combined sewer overflows during heavy rainfall — a problem Bazalgette had noted as a future concern in his original reports.

The Embankment: Beauty from Engineering Necessity

To house the Northern Low Level Sewer running alongside the Thames, Bazalgette built the Victoria Embankment (1862–1870), which reclaimed 37 acres of land from the river, narrowed the Thames by about 100 feet, and provided the space for the underground sewer, the newly built Metropolitan (Circle) Line, and the surface road. The embankment transformed central London's riverfront from a fetid, irregular shoreline of warehouses and mud into a formal, tree-lined promenade that remains largely unchanged today.

The cholera death rate in London fell dramatically after the system became operational: from the epidemic levels of the 1840s–50s to near zero by the 1870s. The last major London cholera epidemic was in 1866, confined to an area of East London (Whitechapel) that was the last district connected to the new sewerage system. The correlation was unmistakable even to those who still doubted germ theory. Bazalgette was knighted in 1875. His system is widely credited, alongside the contemporaneous development of clean water infrastructure by similar engineers in other British cities, with the dramatic reduction in Victorian-era mortality from waterborne disease that constitutes one of the most significant public health achievements in history.